Chediak-Higashi syndrome (CHS) is a rare immuno-deficiency disease with manifestations involving alterred hemostasis, an increase in the frequency of malignancies, abnormal function of lysosomes with resultant lack of "Natural Killer" activity, and an increase in a specific subset of T-lymphocytes. The gene responsible for the syndrome has not been characterized in either the human or murine system, although the chromosomal location of the gene causing the analogous syndrome in mice (bg) has been identified. The goals of this project are: 1) Generate a murine "jumping library" to identify new probes close to bg, 2) Define restriction fragment length polymorphisms (RFLP) with these probes through cross hybridization with human DNA, 3) Determine genetic linkage of the probes to the CHS gene by RFLP and family analysis, 4) analyze human and murine northern blots to identify transcripts of the putative gene and 5) sequence putative CHS genes and predict the protein product. The technology for identifying a gene by "reverse genetics" on the basis of its chromosomal location exists and should be facilitated in this instance by the presence of an animal model for which the gene has been previously mapped. Identification of the CHS gene should provide information about hemostasis, immune surveillance, lysosomal function, and the in vivo function of gamma delta T-lymphocytes. Dr. Randall Holcombe is completing training in the medical subspecialties of hematology and oncology and has already initiated a productive research program concerning CHS. He has developed expertise in the molecular biological techniques required for the successful completion of the research program described herein over the prior two years. The Department of Genetics, where the bulk of the research will be performed, has the equipment necessary for recombinant DNA research, with tissue culture and animal facilities. The Hematology Division and the Department of Genetics sponsor journal clubs, lab meetings, and several lecture series, and provide an exciting and stimulating environment for research.